The ultrastructure of contact lens induced changes.

The endothelium of 15 human corneas was studied with specular and electron microscopy after exposure to a thick, low water content, soft contact lens (SCL). Five control corneas (no lens wear) were studied using the same methods. SCL wear produced obvious changes in endothelial morphology in 12 of the 15 eyes. With specular microscopy, the changes consisted of an apparent increase in separation of cells and development of areas of loss of membrane reflectivity (blebs). When viewed with electron microscopy, the changes in the same corneas consisted of oedema in the nuclear area of the cells and bulging of the posterior endothelial surface, in some cases over an area of several cells. In 4 cases, the cellular oedema was marked showing both intracellular and intercellular vacuoles. It was concluded that the transient endothelial changes seen with specular microscopy following SCL lens wear were produced by alterations in the contour of the posterior endothelial surface resulting from disturbance to the endothelial environment.